Most astral-plane text is emojis like U+1F4DA BOOKS (📚), but some
languages like Osage have their alphabet entirely in the supplementary
multilingual plane as well. For proper support of languages like Osage,
and newer emojis, the UTF-8 decode and encode functions need to properly
handle codepoints above U+FFFF, which are represented by a surrogate
pair in Javascript strings.
I (Flibbles) changed it so that lists generated by stringifyList
would always be compatible with a filter parser, but since lists
are not, and never will be, a subset of filters, there isn't a
point.
More importantly, wrapping negative numbers like "-7" in brackets
would mess up some math stuff.
